This invention relates to a drive system for an elongate irrigation pipeline.
A variety of devices have previously been designed for moving long sections of irrigation pipelines over the ground. In the past some such systems included multiple wheel support devices connected to the irrigation pipeline at spaced intervals there-along, with each wheel support having its own independently operated drive motor. This has been costly and cumbersome in that an operator was required to traverse the length of the pipeline to physically start and control the independent motor drive units. Another form of prior device includes a single motor which rotates the pipeline, with the pipeline itself serving to provide rotative force to the wheel supporting it. Since such pipelines are very long and somewhat flexible this often results in inconsistent rotation of the pipeline so that variations in positioning of sprinklerheads on the pipeline and variations in positioning of sections of the line occur.
A third style of prior drive system is exemplified by the device illustrated in the Jensen U.S. Pat. No. 2,946,515 in which power is transmitted from a drive motor through an elongate drive shaft extending the entire length of the string of pipe. Not only does this result in the need for complex mechanical systems to transmit power from the drive shaft which is rotating both about its own axis and also rotating about the axis of the pipeline, but since the drive shaft itself has a tendency to wrap, or twist, along its length due to torsional forces, it will also result in inconsistencies of the drive for the line along the length of the line.
A general object of the present invention is to provide a novel drive system for an irrigation pipeline which eliminates the previously discussed advantages of prior systems.
Another object of the invention is to provide such novel drive system which is simply an economically constructed, and due to the simplicity of construction may provide long term operation with minimum maintenance requirements.
More specifically, an object of the invention is to provide a novel drive system for an irrigation pipeline wherein each wheel support may have its own fluid actuated drive system and wherein the fluid pressure for actuating such drive system may be provided from a single source, preferably from one end of the pipeline.
Yet another object of the present invention is to provide such novel apparatus in which fluid pressure supply and exhaust lines for supplying and exhausting fluid from pressure actuated motors in the various drive systems spaced longitudinally along the pipeline may be routed past stationery elements in the system and still be permitted rotation with the pipeline along the length thereof.